I love a good ramble @Overthinker , I've only recently been diagnosed with bipolar 2 and I am looking back at a lot of things in my life and going "huh, that makes sense then" including having very low confidence / self esteem but then sometimes way too much confidence which in retrospect was hypomania. Makes sense since it felt like "hollow" confidence and was not sustainable or conducive to useful behaviour.
As for people understanding you... yep it has been a big issue for me too, I guess that is just how it is with a mental illness. Very hard to relate sometimes, well i wrote in another thread about that.
You and @Doog seem to really be getting all the letters between you. I have talked to people with some of the things like ADHD and OCD before joining these forums and they certainly seem to have their own unique flavour of difficulty. Thought I might have had BPD before getting a bipolar diagnosis because there is a lot of similar stuff in there.
Like always I wish there was more general awareness and education on mental illness. If I had known properly about anything (anxiety, depression, the fact that bipolar 2 exists) it would have made my life easier. OK going on a tangent to a tangent. Oh one more thing about regressing since you mentioned it, as I'm sure you know and everyone else with mental illness there isn't like a linear progression.
That is the public perception where there is something wrong and you just get better and better until you are fixed but the reality is you bounce all over the place and with a lot of trial and error and hopefully understanding and help from others you eventually have tools that can help but are not guarantees.
I will get off my soapbox now. I don't even know where I found this thing they don't sell soap in boxes like this anymore.